The complex life of coral

Dr Tracy Ainsworth’s research is changing our understanding of the tiny coral animals that built Australia’s iconic Great Barrier Reef. Tracy and her colleagues at James Cook University in Townsville have found that the process of coral bleaching is a far more complex than previously thought, and begins at temperatures lower than previously considered. And she’s done so by applying skills in modern cell biology which she picked up working in neuroscience laboratories.

Her achievements won her a $20,000 L’Oréal Australia For Women in Science Fellowship in 2011, which she is using to study the low light, deep water reefs that underlie tropical surface reefs at depths of 100 metres or more. In surface reefs, the coral polyps—relatives of jellyfish and anemones that construct the reef’s limestone scaffolding—form a symbiotic relationship with single-celled algae called dinoflagellates.

But the reef also supports communities of bacteria. They live in a mucous coating which the polyps secrete to protect themselves from wave action and the scouring of sand and sediments. And they provide another layer of protection, producing chemical defences against less benign infective bacteria and microbes that can cause disease. This interaction seems to be important for corals, Tracy found.

Now she wants to investigate what’s happening in the deep reefs. This is a world far removed from the bright, colourful, sunlit environment we associate with coral. It’s a place with little or no photosynthesis to provide the energy for reef construction and maintenance. But the biological communities still include algae and are equally diverse. They may even serve as refuges from which devastated shallow reefs can repopulate.